Global Maize Project in China: Liufangzi, Gongzhuling, Jilin Province

The long-term field trial of the Global Maize Project was initiated at Liufangzi, Gongzhuling city, Jilin Province in 2009. The successive mono-cropped spring maize, the dominant cropping system in northeast China, was the test crop for this experiment during the last eight years. Maize grain yield and nitrogen (N) use efficiency were investigated to compare the performance of two main treatments, the ecological intensification (EI) and the farmers’ practices (FP).

The nutrient application rate in the EI treatment was 200-75-90 kg N-P₂O₅-K₂O/ha, while the FP treatment received 251-145-100 kg/ha. The study also had three subplots that created three different N application regimes: (1) N applied in all three years, (2) N applied in two of every three years, and (3) no N applied in any year. In 2016, spring maize was planted during April 26 to May 1, and harvested at the end of September.

The three subplots of the EI treatment produced grain yields of 12.8 t/ha, 12.7 t/ha, and 2.4 t/ha in 2016, and the corresponding values for the FP treatment were 12.0 t/ha, 11.4 t/ha, and 2.7 t/ha, respectively. We used the agronomic efficiency (kg grain yield increase per kg N applied as compared to a subplot where no N was applied, AEN) and the partial factor productivity (kg grain yield per kg N applied, PFPN) to evaluate the N use efficiency. The AEN of the two subplots of the EI treatment where N was applied were 52.0 and 51.7 kg/kg, which were significantly higher than the AEN values of the comparative subplots of the FP treatment (37.1 kg/kg and 34.5 kg/kg). Likewise, the PFP values of the two subplots in the EI treatment were also higher (63.9 kg/kg and 63.6 kg/kg) when compared to the FP treatment (47.9 kg/kg and 45.3 kg/kg).